Water ski structure

ABSTRACT

An improved water ski structure having a conventional ski body with the addition of a pair of parallel depending rails on the lower ski surface defining a central channel therebetween. The forward portions of the rails are of a constant depth and merge at the forward end into the upwardly curved front end of the ski, and the rear portions of the rails are provided with a plurality of short sequential inclined planes having a progressively greater angle of inclination toward the rear end of the ski; the planes being inclined forwardly and upwardly to provide greater lifting power for the ski.

United StatesPat-ent 1 9] Silverstein WATER SKI STRUCTURE [21] Appl.No.: 202,345

[52] U.S. Cl 9/310 A, 114/665 S, 280/1 1.13 Y [51] Int. Cl. A63c 15/00[58] Field of Search 9/310 R, 310 A-310 E; 280/1 1.13 Y; 114/665 S, 66.5R

[56] References Cited 7 UNITED STATES PATENTS 1,223,320 4/1917 Curtisset al 114/665 S 1,620,349 3/1927 Hickman 114/665 S 3,099,025 7/1963Merkley et al.. 9/310 A 2,143,545 1/1939 Currier 280/11.13 Y 3/1965Amsbry: 9/310 A Rivard 9/310 A X Pope, Jr. et a1 9/310 A PrimaryExaminer-Milton Buchler Assistant Exar'ninerPaul E. SaubererAttorneyCarl F. Geppert [57] ABSTRACT An improved water ski structurehaving a conventional ski body with the addition of a pair of paralleldepending rails on the lower ski surface defining a central channeltherebetween. The forward portions of the rails are of a constant depthand merge at the forward end into the upwardly curved front end of theski, and the rear portions of the rails are provided with a plurality ofshort sequential inclined planes having a progressively greater angle ofinclination toward the rear end of the ski; the planes being inclinedforwardly and upwardly to provide greater lifting power for the ski.

10 Claims, 6 Drawing Figures PATENTED I 2 75 WATER SKI STRUCTURE Thepresent invention relates to an improved water ski structure and moreparticularly to a water ski structure utilizing inclined planes on thebottom surface thereof to provide a greater lifting effect for the skicarrying a skier.

Conventional water skis provide an elongated flat lower surface with anupwardly curved forward end and a foot binding on the flat uppersurface. Trick or stunt skis require a flat under surface andconventional skis are often provided with one or a pair of shallowwooden rudders or a deep single metal keel utilized for stability and toenhance the ease of maneuvering the skis while being pulled through thewater. However, beginning from a stationary position in the water forthe skier to a normal planing position of the skis is difficult toaccomplish as both the boat and skier must build up speed from theirstationary positions. The present ski structure alleviates this startingproblem as well as enhancing the planing position of the skis.

Among the objects of the present invention is the provision of animproved water ski structure providing a distinct catamaran effect. Apair of depending parallel rails or ribs are formed on the undersurfaceof the ski along the longitudinal edges thereof to define a central openchannel. The use of the rails separated by the central channel providesa catamaran effect for the ski in planing position.

Another object of the present invention is the provision of an improvedwater ski providing a greater lifting effect for starting from astationary position in the water and an improved planing position. Thisski structure permits towing of water skiers utilizing less horsepowerfor the boat as the inertia, water resistance and towing force aresubstantially reduced. The parallel depending rails each has a forwardportion of a constant depth and a rearward portion having a plurality ofinclined planes formed thereon, with each inclined plane being ofsubstantially equal length but of gradually increasing angularity anddepth toward the rear end of the ski. The inclined planes on each railprovide a greater lifting effect in starting with the skis and skier inthe water and an improved more horizontal planing when the skier isriding on the surface of the water.

A further object of the present invention is the provision of animproved water ski structure where a pair of skis can be used for normalskiing or a single ski can be used as a slalom ski. The parallel railsand'central channel reduces the frictional area of contact with thewater and provides greater balance and stability in use. A relativelydeep center keel is mounted in the channel adjacent the rear end of theski to improve stability and maneuverability of the ski.

Further objects are to provide a construction of maximum simplicity,efficiency, economy and ease of assembly and operation, and such furtherobjects, advantag'es and capabilities as will later more fully appearand are inherently possessed thereby.

In the drawing:

FIG. 1 is a side elevational view of the improved water ski structure ofthe present invention.

FIG. 2 is a bottom plan view of the water ski structure.

FIG. 3 is a perspective view of the water ski structure.

FIG. 4 is an end elevational view taken from the rear end of the ski.

FIG. 5 is a vertical cross sectional view taken on the line 55 of FIG.1.

FIG. 6 is a vertical cross sectional view taken on the line 6--6 of FIG.1.

Referring more particularly to the disclosure in the drawing wherein isshown an illustrative embodiment of the present invention, FIGS. 1, 2and 3 disclose a water ski 10 having a generally flat upper surface 11and an upwardly curved forward end or toe portion 12. This ski may beone of a pair of identical skis for a water skier; however, the presentski is shown as a slalom ski utilized for single ski operation. Thus, onthe upper ski surface 1 1 is positioned a stationary toe piece 13 formedof a flexible piece of rubber or similar resilient material secured atits edges to the ski by a pair of metal bars 14,14, and a flexibleadjustable heel piece 15 formed of the same resilient material ismounted on a plate 16 to cooperate with the toe piece to receive onefoot of the skier; the plate 16 having an adjustment slot 17 in the rearportion cooperating with a clamping screw 18 for anchoring in adjustedposition. A rear toe piece 19 clamped onto the ski by metal bars 21,21is stationary to receive the toes of the rear foot of the skier and isalso formed of flexible material as is conventional in water skiconstruction.

Depending from the flat undersurface 22 of the ski are a pair ofgenerally parallel integral elongated rails or ribs 23,23 at the outeredges of the ski 10. Each rail extends from a curved surface 24 merginginto the undersurface 22 of the ski adjacent the curved forward end 12to the rear ene 25 of the ski; the rails defining a central longitudinalchannel 26 therebetween of a substantially constant width. Mounted inthe channel 26 adjacent the rear end 25 is a relatively deep keel orrudder 27 which extends for approximately two-thirds of its depth belowthe rails 23,23 at its deepest point. The keel or rudder 27 isadvantageous in providing for stability against excessive lateralmovement of the ski and prevents any fishtailing action of the ski. Therails 23 and the central channel 26 therebetween provides a catamaraneffect to enhance balance and stability of the ski and provide betterweight distribution of the skier.

The forward approximately one-third of each rail 23 is of a constantdepth as at 28 and the rearward approximately two-thirds of each rail isprovided with a plurality of inclined planes 29, 31, 32, 33, 34 and 35of substantially equal length. However, each plane is of a slightlygreater angularity than the previous plane to wards the rear end 25 ofthe ski, and each shoulder 36,37,38,39 and 41 and the rear edge 42 ofthe last plane are progressively deeper.

As seen in FIG. 1, the dotted line 44 passes through and discloses thatthe deepest point of each shoulder lies in a common plane parallel toboth the lower surface 22 of the ski and the channel 26 and the uppersurface 11. Thus the shoulder 36 indicates the shallowest inclined plane29, while the shoulders 37, 38, 39 and 41 increase in depth by asubstantially constant increment, with the angularity of each plane 31,32, 33, 34 and 35 also increasing by a substantially constant increment.The shoulder 43 between the lower surface 28 of the forward portion ofthe rail 23 and the inclined plane 31 extends to the common plane 44 ofthe bases of the shoulders and is of a depth of slightly less than orequal to the depth of the shoulder 36.

The center channel 26 has a width of approximately 20 to 25 percent ofthe total width of the ski at its maximum width and insures directionduring skiing. This channel provides a passage for air to move under theski and produces an aerodynamic lifting action on the ski, which raisesthe ski to the surface of the water. The most common method of startingon water skis for the skier is to start in the water in a crouchedposition with the skis parallel and pointing upward at a steep angle;the tow rope from the boat passing between the upper ends of the skiswith the tow bar grasped by the skier. As the boat is started from itsstationary position to obtain proper speed for skiing, the flat bottomsurfaces of conventional skis provides a high resistance force as theskis and skier are pulled through the water until the skis reach aplaning position at a slight rearward angle from the horizontal as theskier leans away from the force of the boat. For novices, the highresistance in starting from a position in the water provides thegreatest deterrent to actual skiing, as most falls occur duringstarting.

The present water ski design overcomes this problem by the use of theinclined planes 29, 31, 32, 33, 34 and 35 on the rails 23. Rather thanthe water pushing against a single flat surface of a conventional ski,the water is pushingagainst the six inclined planes of progressivelyincreasing angularity. As these planes are inclined to the lower surfaceof the ski, the action of the water on these planes acts to quickly urgethe ski towards a horizontal position with less effort. Thus the skiachieves a planing position much quicker and under less pulling forcethan a conventional ski.

Once a planing position has been reached, the inclined planes act toprovide a more nearly horizontal position for better planing with lesseffort so that the skier does not tire in the back and shoulders asreadily as with conventional skis. If the improved ski structure is usedas a single ski, the greater horizontal planing position produces verylittle spray, and, when the skier crosses the wake of the boat inmaneuvering the ski, the lifting action of the rear inclined planes canaffect the ski to leave the crest of the wave and become momentarilyairborne. Also, the present design reduces the frictional area ofcontact between the ski surface and the water and thus reduces the forcerequired for the boat towing the skier.

Although the rails 23,23 are disclosed to be integral with the body ofthe water ski 10', conventional water skis can be readily altered to thepresent design by the attachment of a pair of rails of the properconfiguration to the undersurface of the skis by any suitable securingmeans. Also, although a single deep keel 27 is shown mounted in thecenter channel 26, my invention comprehends the use of additionalrudders on the rear portion of each rail in addition to or as asubstitute for the center keel.

I claim:

1. A water ski having an elongated ski body and a pair of substantiallyparallel rails depending from the undersurface of the ski body andextending longitudinally along the edges thereof, said rails defining acentral channel therebetween of a substantially constant width andopening into the rear edge of the ski, cach rail including a forwardportion of a substantially constant depth and merging at the front endinto the undersurface of the ski at a point spaced from the forward endthereof, and a rear portion extending to the rear end of the ski, saidrear portion having a plurality of inclined planes separated by trailingedges forming shoulders of progressively increasing depth, the planesbeing of progressively increasing angularity toward the rear end of theski.

2. A water ski as set forth in claim 1, in which said inclined planesare all of substantially equal length.

3. A water ski as set forth in claim 1, in which said forward portion ofeach rail is approximately one-third the total length of the rail andthe rear portion is approximately two-thirds the total length thereof.

4. A water ski as set forth in claim 1, in which a shoulder separatesthe forward rail portion providing a stabilizing surface from theadjacent inclined plane of least angularity on the rear rail portion,said planes being inclined downwardly and rearwardly away from theforward rail portion.

5. A water ski as set forth in claim 4, in which the points ofintersection of each shoulder with the next succeeding inclined planeall lie in a common horizontal plane parallel with the upper surface ofthe ski.

6. A water ski as set forth in claim 5, in which said center channel isas deep as the rails and is deeper than the common horizontal planedefining the intersections of the shoulders with the inclined planes.

7. A water ski as set forth in claim 1, in which said center channel isof a width equal to approximately 20 to 25 percent of the maximum widthof the ski.

8. A water ski as set forth in claim 1, including at least one rudder onthe undersurface of the ski to provide lateral stability thereto.

9. A water ski as set forth in claim 8, in which a single relativelydeep rudder is mounted in the center channel adjacent the rear end ofthe ski and depends for at least half of its maximum depth below therails.

10. A water ski as set forth in claim 1, in which said rails are formedintegral with the ski, said ski having an upwardly curved forward end,and the forward portion of each rail having a curved forward end merginginto the ski adjacent the curved forward end of the ski.

I? t: 3 k t

1. A water ski having an elongated ski body and a pair of substantiallyparallel rails depending from the undersurface of the ski body andextending longitudinally along the edges thereof, said rails defining acentral channel therebetween of a substantially constant width andopening into the rear edge of the ski, each rail including a forwardportion of a substantially constant depth and merging at the front endinto the undersurface of the ski at a point spaced from the forward endthereof, and a rear portion extending to the rear end of the ski, saidrear portion having a plurality of inclined planes separated by trailingedges forming shoulders of progressively increasing depth, the planesbeing of progressively increasing angularity toward the rear end of theski.
 2. A water ski as set forth in claim 1, in which said inclinEdplanes are all of substantially equal length.
 3. A water ski as setforth in claim 1, in which said forward portion of each rail isapproximately one-third the total length of the rail and the rearportion is approximately two-thirds the total length thereof.
 4. A waterski as set forth in claim 1, in which a shoulder separates the forwardrail portion providing a stabilizing surface from the adjacent inclinedplane of least angularity on the rear rail portion, said planes beinginclined downwardly and rearwardly away from the forward rail portion.5. A water ski as set forth in claim 4, in which the points ofintersection of each shoulder with the next succeeding inclined planeall lie in a common horizontal plane parallel with the upper surface ofthe ski.
 6. A water ski as set forth in claim 5, in which said centerchannel is as deep as the rails and is deeper than the common horizontalplane defining the intersections of the shoulders with the inclinedplanes.
 7. A water ski as set forth in claim 1, in which said centerchannel is of a width equal to approximately 20 to 25 percent of themaximum width of the ski.
 8. A water ski as set forth in claim 1,including at least one rudder on the undersurface of the ski to providelateral stability thereto.
 9. A water ski as set forth in claim 8, inwhich a single relatively deep rudder is mounted in the center channeladjacent the rear end of the ski and depends for at least half of itsmaximum depth below the rails.
 10. A water ski as set forth in claim 1,in which said rails are formed integral with the ski, said ski having anupwardly curved forward end, and the forward portion of each rail havinga curved forward end merging into the ski adjacent the curved forwardend of the ski.